1. Test Case 1 : Mixed convection in vertically flowing heated pipe (buoyancy aiding or opposing) Problem specifications:  Re=2650  Pr=0.71  Wall constant heat flux  Boussinesq approximation Heat transfer Regimes:  Gr/Re 2 =0.000  Forced Convection  Gr/Re 2 =0.063  Forced/Mixed Convection  Gr/Re 2 =0.087  Re-Laminarization  Gr/Re 2 =0.241  Recovery KNOO CFD @ Manchester: Heat transfer test cases

2. AGR working scheme Relevance to AGR and VHTR

3. V gradient away from wall => Turbulence increase V gradient nearer wall => Turbulence decrease buoyancy aiding buoyancy opposing Buoyancy aiding or opposing vertical pipe flow

4. Nu/Nu0 against ‘buoyancy parameter’, [Hall and Jackson ]

5. STAR-CD Quasi DNS [Y. Addad ]

6. K-omega not sensitive to buoyancy effect

7. Good predictions by V2F models

8. “standard” STAR k-epsilon model (Lien Chen Leschziner)

9. Results for Fully-Developed Forced Convection. (no buoyancy) Expt. of Polyakov & Shindin

10. Buoyancy aided heated pipe flow Gr/Re**2 = 0.000

11. Buoyancy aided heated pipe flow Gr/Re**2 = 0.063

12. Buoyancy aided heated pipe flow Gr/Re**2 = 0.087 (relaminarization)

13. Buoyancy aided heated pipe flow Gr/Re**2 = 0.087 (relaminarization)

14. Buoyancy aided heated pipe flow Gr/Re**2 = 0.087 (relaminarization)

15. Buoyancy aided heated pipe flow Gr/Re**2 = 0.241 (recovery)